Michael Dunn will spend the rest of his life in prison for the shooting death of a teenager in Florida.

Dunn’s sentencing on Friday closes a chapter in the “loud music” case that began with a 2012 argument between Dunn and 17-year-old Jordan Davis in the parking lot of a Jacksonville gas station. The terms of the sentence were not a surprise: Dunn was found guilty of first-degree murder on Oct. 1, and after prosecutors decided against seeking the death penalty, the life sentence without parole was mandatory.

Circuit Judge Russell Healey told Dunn in court that his “life is effectively over.”

During the sentencing hearing Friday, Dunn, 47, issued what appeared to be his first public apology to the dead teenager’s family.

“I want the Davis family to know I truly regret what happened. I’m sorry for their loss,” CNN quoted Dunn as saying before receiving his sentence.”If I could roll back time and do things differently, I would.”

In November 2012, Dunn shot Davis at a gas station after an argument involving the music coming from a vehicle carrying Davis and three other teenagers.

Dunn fired 10 times at the vehicle, shooting even as the vehicle pulled away. Davis died soon after being shot, while the two other people in the car narrowly missed being shot themselves.

Dunn returned to his hotel and drove home to Brevard County the next day. He was arrested several hours later.

Earlier this year, a jury convicted Dunn on some of the lesser charges he faced for Davis’s death, but the jury was deadlocked on the first-degree murder charge. Some of the jurors felt Dunn acted in self-defense.

Dunn was retried on the first-degree murder charge. A second jury convicted him in less than a week.

Prosecutors argued during the second trial that Dunn fired with lethal intent. In both trials, Dunn testified that he responded with deadly force because he reasonably believed his life was in danger.

Mark Berman contributed reporting.